Foam stabilizing agent



Patented July 11, 1939 7 PA NTZQF FOAM STABILIZING AGENT Cameron B. Holter and llrnestL. Stewart, Port Arthur, Tex., assignors to The Texas Company, New York, N. Y., a corporation of Delaware No Drawing. Application May 27, 1937,

Serial No. 145,064

' -6 Claims. (Q1. 23-11) This invention relates to foam stabilizing agents, and is primarily for use in solutions which, upon mixture in accordance with general practice, are, capable of forming blankets of foam. These foam blankets are composed of carbon dioxide or from gases which are non-supporting to combustion. The reaction results in numerous gas bubbles, providing a blanket which will shutoff the supply of oxygen to a fire, and in this manner a, very excellent fire extinguishing composition is produced.

v A stabilizing agent is required in order to increase the toughness and tenacity of the foam in order. that the blanket will be stable, and not ;easily; disintegrated or broken. The theory of the stabilizing agent is that it will increase the surface tension of the water films, which surround the gas bubbles in the foam, so that in this manner a blanket substantially impenetrable to oxygen and other gases will be formed to smother the fire.

In the past various foam stabilizing agents -have been employed. Our improved stabilizing agent comprises two materials which in combination have been found very effective for the ,purposedescribed; One of said materials consists essentially of the alkali metal salts of the complex sulfonic acids produced by sulfonating V a mixture of a petroleumhydrocarbon oiland an added: aromatic hydrocarbon selected from the group consisting of benzol, toluol and diphenyl. The other material referred to is a water dispersible colloid which swells in water and has ,substantially the colloidal characteristics of gelat nl The alkali metal salts used inmaking the foam stabilizing agent of this invention are of the same general type as those described in a co-pending 0 application by Robert R. Thurston, Serial No. 670,515, filed May 11, 1933. As disclosed in said application, these alkali metal salts are preferably made by sulfonating a mixture of 9060% by weight of a p troleum fraction selected from a {the group consisting of petroleum distillate lubricatingpil and solventextracts of petroleum lubricating oil, with 10-40% of an aromatic hydrocarbon selectedfrom the group consisting of benzol, toluol and diphenyl, to form petroleum 5Q hydrocarbon-aromatic sulfonic acids, and neutralizing the resultant sulfonated oily layer with an excess of an alkali metal base to form alkali metal salts of the petroleum hydrocarbon-aromatic sulfonic acids. It has been shown that the aromatic materialenters into chemical combination with the petroleum hydrocarbon during the 's'ulfonation reaction to form a complex sulfonic acid which may be termed a petroleum hydrocarbon-aromatic sulfonic acid, by reason of 'the' fact that distillationof the product made with benzol, for example, does not liberate any but a small portion of the benzol used. Without with the use of up to 40% benzol.

' The following examples are given of methods which may be followed in the manufacture of said alkali metal salts:

Example 1 The following materials are delivered into a treating vessel which preferably is provided with a' steam jacket around the body thereof for heating the contents of said vessel: 7

Percent by weight Petroleum hydrocarbon oil obtained as a distillate from naphthene base crude, said distillate comprising a wide range of lubricating oil frac v 83 Commercial benzol 17 The mixture of petroleum hydrocarbon oil and benzol is heated to a temperature of the order of 'to F., andconcentrated sulfuric acid is added to the mixture. The equivalent of approximately 83% by weight of 100% acid is used, based onthe weight of the mixture of petroleum hydrocarbon oil and benzol above described. Either fuming acid or-98% acid may be used, the amount required depending upon the concentration of acid used The acid is added slowly over a period of about three hours. The mixture is agitated while the acid is being added thereto, and such agitation is continued for about three hours after all of 'the acid has been added. Thereafter about 54% by weight of water is added to the mixture, based upon the weight of the mixture before adding the acid. The water is added slowly, over a period of about forty-five -minutes. The temperature of the mixture is raisedto' about 190 F. while adding the water.

The mixture is agitated while adding the water,

and such agitation is continued for about 30 ,Extract obtained by treatment with minutes after all of the water has been added.

terial produced by the reaction of the concen trated sulfuric acid on the mixture of petroletmif hydrocarbon oil,and ,benzo1,1 is neutralized with Baum sodium hydroxide, the resulting prod-, uct having a free alkali content of about from 0.25% to 1% NaOH. This material isfinally' dried by evaporation of water.

Ewamzlle 2 The following materials are delivered intosaidtreating vessel: 1'

Percent Y liquid sulfur dioxide of a petroleum hydrocarbon Commercial benzol 18 This mixture is processed in the same manner as the mixture referred to. in Example 1. The amount of acid used is'about'76%, and the amount of water used is about 48%, based on the weight of the mixture of petroleum hydrocarbon oil extract and benzol above described.

It has been .found that 'very satisfactory results can be obtained by sulfonating a petroleum hydrocarbon oil which contains a high percentage of naphthenic compounds as distinguished from parafI-lnic compounds. Thus excellent results are obtained when using lubricating oils Likewise very satisfactory results are obtained when using the extracts obtained by treating either a naphth ene base lubricating oilor a paraffine base lubricating oil with liquid sulfur dioxide, furfural, or

' I other solvents which have the effect of producing an extract containing a relatively high percentage of the naphthenic compounds originally present in the oil. a

Any of the materials in the group consisting 1 of benzol, toluol and diphenyl may be used in the manner above described, toluol and diphenyl producing results which are similar to those obtained when using benzol.

While in Example 1, above, it is stated that "the acid material produced by the reaction of .substances as gelatin, acacia, tragacanth, and

the like. L

Our improved foam stabilizing agent, consisting of the alkali metal salts above described, together with one or more of said water dispersible colloids, can be readily employed with the usual foam producing solutions which, for example,

may consist of bicarbonate of soda and aluminum sulphate solutions, arranged. in separate combyweight 'guishing the 'fire.

is formed. actual use in connection with fires the results partments of a fire extinguishing apparatus. In this type of foam producing solution the foam stabilizing agent is preferably added to the alkali chamber of the extinguisher, which contains the bicarbonate of soda solution.

The following is an example of foam producingsolutions consisting, respectively, of aluminum sulphate and bicarbonate of soda, in which our improved stabilizing agent, consisting ,of the two materials above described, has been added t6 the bicarbonate of soda solution Percent A solution I by weight Aluminum sulfate (hydratedlh i; 43 Water Balance B solution; Sodium bicarbonate 8 Alkali metal salts such as those described in Examples 1 and 2 0.6 Gelatin 0.0075 -Waterr s e ;l Balance The -A solution and the B solution are orsuch as the one described in E 82 a dinarily mixed at the scene of the fire to produce the desired foam producing'solution for extin- Substantially equal parts of each solution, for example, may be used.

The amount of the above described alkali metal salts which is required may vary within certain limits. Ordinarily the amount required will be from 0.1% to 1% by weight of said alkali metal salts, based on the weight of'the mixture which is obtained by mixing the two solutions" above described. I

The amount of said water dispersible colloids scribed. From 0.5% to 2% by Weight of said water dispersible colloidsmay be used, based on the amount of said alkali metal salts which is used.

We have observed that with the use of our foam stabilizing agent a blanket of great tenacity It is impenetrable to oxygen, and in have been highly satisfactory and are superior 'to those obtained'with the fire extinguishing solutions which are now on the market. In an analytical test 50 c. 0. each of the"A solution and the B solution above described (a total of 100 c. 0.) were mixed and the following observations made: I Volume after 2 minutes c. c. 1000 Volume after agitating c. c. 1970 A similar fire extinguishing solution which is now available commercially, and which does not contain our improved stabilizing agent, was tested in the same manner and the following results noted:

Volume after 2 minutes--. c. c. 850 Volume after agitating c. c. 820

Obviously many modifications and variations 7 of the invention, as hereinbefore set forth, may

be made without departing from the spirit and e scope thereof, and therefore only suchlimitations should be imposed as are indicated in the appended claims.

' We claim:

troleum hydrocarbon-aromatic sulfonic acids produced by sulfonating a mixture of a petroleum lubricating oil and an added aromatic hydrocarbon selected from the group consisting of benzol, toluol and diphenyl, and from 0.5% to 2% by weight, based on the amount of said alkali metal salts, of gelatin.

2. A fire extinguishing charge consisting of two solutions adapted to unite to produce gases nonsupporting to combustion, one of said solutions having mixed therewith a foam stabilizing agent comprising the alkali metal salts of petroleum hydrocarbon-aromatic sulfonic acids produced by sulfonating a mixture of the extract obtained by treating a petroleum lubricating oil with a solvent which has the effect of producing an extract containing a relatively high percentage of the naphthenic compounds originally present in said lubricating oil and an added aromatic hydrocarbon selected from the group consisting of henzol, toluol and diphenyl, and from 0.5% to 2% by weight, based on the amount of said alkali metal salts, of gelatin.

3. A fire extinguishing charge consisting of two solutions adapted to unite to produce gases nonsupporting to combustion, one of said solutions having mixed therewith a foam stabilizing agent comprising a relatively large amount of the alkali metal salts of petroleum hydrocarbon-aromatic sulfonic acids produced by sulfonating a mixture of a petroleum hydrocarbon oil and an added aromatic hydrocarbon selected from the group consisting of benzol, toluol, and diphenyl, and a relatively small amount of a water dispersible colloid selected from the group consisting of gela tin, acacia and tragacanth.

4. A fire extinguishing charge consisting of two solutions adapted to unite to produce gases non-supporting to combustion, one of said solutions having mixed therewith a foam stabilizing agent comprising from 0.1% to 1% by weight of the alkali metal salts of petroleum hydrocarbonaromatic sulfonic acids produced by sulfonating a mixture of a petroleum lubricating oil and an added aromatic hydrocarbon selected from the group consisting of benzol, toluol and diphenyl, and from 0.001% to 0.01% by weight of gelatin.

5. A fire extinguishing charge adapted to produce a tenaceous foam comprising as an essential ingredient thereof a stabil'ming agent consisting of alkali metal salts of petroleum hydrocarbonaromatic sulfonic acids produced by sulfonating a mixture of 90-60% by weight of a petroleum fraction selected from the group consisting of petroleum lubricating oil and solvent extracts of petroleum lubricating oil, and 10-40% by weight of an aromatic hydrocarbon selected from the group consisting of benzol, toluol and diphenyl, and neutralizing the resulting petroleum hydrocarbon-aromatic sulfonic acids with an alkali metal base.

6. A fire extinguishing charge adapted to produce a tenaceous foam comprising as an essential ingredient thereof a stabilizing agent consisting of alkali metal salts of petroleum hydrocarbon-aromatic sulfonic acids produced by sulfonating a mixture of 90-60% by weight of a pctroleum distillate lubricating oil, and 10-40% by weight of benzol, and neutralizing the resulting petroleum hydrocarbon-aromatic sulfonic acids with an alkali metal base.

CAIVIERON B. HOLTER. ERNEST L. STEWART. 

